The present application relates to and incorporates herein by reference Japanese Applications No. 2000-324181 filed on Oct. 24, 2000 and No. 2001-142212 filed on May 11, 2001.
1. Field of the Invention
The present invention relates to a slide detector.
2. Description of Related Art
Generally, in a conventional slide detector, a contact portion of a slider moves on or across electrodes of a conductor layer provided on a board. However, the contact portion of the slider or the electrodes are made of a silver palladium alloy or a silver nickel alloy. When a liquid fuel from a fuel tank of a vehicle is detected by the slide detector, the silver palladium alloy and the silver nickel alloys react to sulfide in the fuel if sulfide or sulfide impurities are contained in the fuel. Accordingly, the contact portion or the electrodes pick up sulfides and become sulfurized. As a result, a coating is formed between the contact portion and the electrodes thereby causing electrical contact failures and, at worst, entirely preventing the contact and the electrodes from electrically communicating.
In view of the foregoing problems, it is an object of the present invention to provide a slide detector having a slider and a plurality of electrodes in which an electrical contact between a contact member of the slider and the electrodes is satisfactorily maintained by suppressing sulfurization of the contacting members. That is, by preventing sulfur from lodging on the slider contact and the electrode(s), a satisfactory electrical contact is maintained. Further, it is another object of the present invention to provide a slide detector having a slider and an electrode(s), in which either the electrode(s) or the slider contact is made of a gold alloy containing an abrasion resistant metallic component in order to ensure anti-sulfurization and abrasion resistance of the electrode(s) and the contact portion.
According to one aspect of the present invention, in a slide detector, a slider has a contact member that slides on a plurality of electrodes arranged side by side from a resistive layer on a board. The plurality of electrodes are made of a silver alloy including glass, and the contact is made of gold or a gold alloy containing an abrasion resistant metallic component. Thus, when the contact member slides on the electrodes, surfaces of the electrodes on which the contact member slides are coated and become gold plated due to the gold component of the contact member. Accordingly, anti-sulfurization is obtained and electrical contact between the contact member and the electrodes are satisfactorily maintained. The gold alloy contains an amount of gold by weight percent equal to or more than 98% but equal to or less than 99.5% (98%xe2x89xa6wt.% of goldxe2x89xa699.5%).